Pollution and risks of trace elements in the soil environment

Trace elements may be either essential or toxic to organisms. The most common trace elements in soils are Cd, As, Cr, Hg, Pb, Ni, Zn, and Cu. Pollution of trace elements in soils may be natural or anthropogenic, with the latter including agricultural and industrial sources. Different trace elements pose variable potential risks to ecosystems, food safety and human health. Cadmium and As have low phytotoxicity, and a high risk of soil–food chain transfer posing a threat to food safety and human health, whereas Zn, Ni, Cu, and Cr are ecotoxic at elevated concentrations, thereby posing risks to productivity and functions of ecosystems including C and N cycles.